Background: Obstructive sleep apnea has been shown to be associated with impaired glucose metabolism and overt diabetes mellitus. However, the effect of hypoxic episodes on nocturnal glucose regulation in non-diabetic patients is unknown.
Objectives: To investigate the effect of hypoxemia and nocturnal glucose homeosatsis in non-diabetic patients with sleep apnea.
Methods: Seven non-diabetic patients with moderate to severe sleep apnea were connected to a continuous glucose-monitoring sensor while undergoing overnight polysomnography. Mean SpO2 and percentage of time spent at SpO2 < 90% were recorded. The correlation between mean glucose levels, the difference between consecutive mean glucose measurements (glucose variability) and the corresponding oxygen saturation variables were determined in each patient during REM[1] and non-REM sleep.
Results: No consistent correlation was found for the individual patient between oxygen saturation variables and glucose levels during sleep. However, a lower mean SpO2 correlated with decreased glucose variability during sleep (r = 0.79, P = 0.034). This effect was primarily evident during REM sleep in patients with significant, compared to those with mild, oxygen desaturations during sleep (> 30% vs. < 10% of sleeping time spent with SpO2 < 90%) (P = 0.03).
Conclusions: Severe nocturnal hypoxemia in non-diabetic patients with moderate to severe sleep apnea might affect glucose regulation primarily during REM sleep.